Treatment of armor-plates.



llnurisn STATES PATIENT riricie.

BENTON KNOTT JAMISON, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO NATIONAL STEEL REFINING COMPANY, OF \VILMINGTON, DELAWARE, A CQRPORATION OF DELAWARE.

TREATMENT OF ARWTOR=PLATES.

SPECIFICATION forming part of Letters Patent No. 690,962, dated. January 14:, 1902.

Original application filed December 24, 1897, Serial No. 663,284 Divided and this application filed June 16, 1900. Serial lilo. 20,565. (No specimens.

To a whom it may concern.-

Be it known that I, BENTON KNOTT JAM I SON, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in the Treatment of Armor-Plates, of which the following is a specification.

This application is in part a division of IO my application filed December 24:, 1897, Serial No. 663,284. In my said application I described a method of treating armor-plates, which consists in heating a steel plate, pref erably of low grade or mild openhearth I 5 steel, slowly and gradually until it attains a bright-red heat and then with as little delay as practicable immersing it to a depth corresponding with the depth to which it is required to be hardened in a cold bath of hardening liquid capable of yielding hydrocarbon gases and maintaining the bath as nearly as practicable at a temperature of 60 to 70 Fahrenheit while permitting the plate to remain in the bath for a sufficient length of 2 5 time to effect the hardening process, the

hardened portion of the plate being toughened at its face, so that a. plate of three different grades of steel may be obtained. The present invention relates to the bath therein described.

The bath liquid provided by my present invention comprises the following ingredients in the proportions named: sweet spirits of niter, (B. P.,) three ounces; aqua-ammonia,

(specific gravity .88,) three ounces; chlorid of ammonium, six ounces; sulfate of zinc, three ounces; ground alum, (Al 3SO .ri.i1'i SO .24H O.,) three ounces; glycerin, eight ounces; Water, one gallon. A liquid com- 0 posed of the same ingredients has already been proposed for hardening and refining steel, but the proportions of chlorid of ammonium and of glycerin have been considerably less, and I have found by experiment that good results are not attained unless the proportions of these two ingredients are as large as above given.

The order in which the ingredients of my hardening liquid are mixed and the time allowed to elapse between the additions of the 5 several ingredients are important. I first introduce into the water the ground alum and the sulfate of zinc, and I allow the mixture to stand for about twelve hours or longer. I then add the glycerin and afterward as soon as practicable the other ingredients. When all the ingredients have been added and thoroughly mixed, it is desirable to allow the mixture to stand for about twentyfour hours before use.

In addition to the above ingredients I prefer to add one ounce each of sulfate of copper and nitrate of soda, and in this case these ingredients are introduced after the addition of the glycerin.

In order to prevent too rapid evaporation of the solution in use, I prefer to add sufficient machine-oil to cover the surface of the bath.

In practicing the process of my application first referred to in connection with the bath herein set forth it is found that low-grade steel is changed in nature, physical structure, and molecular construction, whereas the tempering of steel in oil simply tempers the steel more slowly than is done by tempering in water and other agents, leaving the steel less hard but somewhat tougher than water-tempered material; and, further, the changes caused by the oil tempering process are So merely temporary and do not change the physical and granular structure of the metal, and such changes of the metal caused thereby can be readily neutralized by reheating and allowing the metal to cool. The plates treated according to my invention can be reheated, forged, and reforged without changing their nature, physical structure, or molecular construction.

More or less strength can be given to the solution by decreasing or increasing the quantity of water; but I have found in practice that the proportions specified give good re sults.

What I claim is- 1. The herein-described solution for the treatment of steel, comprising the following ingredients in substantially the following prog Y senses:

portions: sweet spirits of niter, three ounces; 1 ounces; ground alum, three ounces; glycerin, aqua-ammonia, three ounces; chlorid of ameight ounces; sulfate of copper, one ounce; inonium, six ounces; sulfate of zinc, three nitrate of soda, one ounce; water, one gallon.

ounces; ground alum, three ounces; glycerin, i In witness whereof I have hereunto signed 15 5 eight ounces; Water, one gallon. my name in the presence of two subscribing 2. The herein-described solution for the witnesses. treatment of steel, comprising the following ingredientsinsubstantiallythe following pro- LENTON KNUI T JAMISON' portions: sweet spirits of niter, three ounces; Witnesses:

l0 aqua-ammonia, three ounces; chlorid of am- HENRY RAINEY,

monium, six ounces; sulfate of zinc, three l CHAS. M. ALFORD, Jr. 

